1. Field of the Invention
The present invention relates to a communication system and a method for using a communication network therewith, and in particular, to a method for using any of communication systems, such as a mobile communication network, public telephone network, and private network, that use different communication technologies.
2. Description of the Related Art
Today communication networks, such as a mobile communication network, public telephone network, and private network, can be connected to the Internet by using the IP (Internet Protocol) and allows data to be sent and received to and from each other over the Internet.
A public telephone network is a telephone network that uses cables and has switches connected to telephones at individual homes and companies. A mobile terminal can be connected to the telephone by using wireless communications, such as Bluetooth and IrDA (Infrared Data Association), or cable communications.
The public telephone network is called PSTN (Public Switched Telephone Network). ISDNs (Integrated Services Digital Networks) also fall into this category. The telephone may be a public telephone.
A mobile communication network is a network that uses base stations to wirelessly accommodate mobile terminals. PDC (Personal Digital Cellular), CDMA (Code Division Multiple Access), PHS (Personal Handyphone System) fall into this category.
A private IP network is a network constructed by using the IP, called intranet, and used as LANs (Local Area Networks) in companies and SOHOs (Small Office Home Offices). Mobile terminals can be connected to an adapter in the private IP network by wireless or using cables to perform the same operations as those of a host terminal residing in the private IP network.
However, in the mobile communication system using the conventional mobile communication network, a mobile terminal can move only within the mobile communication network. Therefore another terminal must be used when a public telephone network or other networks are used.
If a network other than the mobile communication network is used through the mobile terminal, charges for both networks must be paid separately because each of the networks uses an independent charge accounting system.